Adjustable grip for bowling ball



July 22,1958 L. R. QESTOR' v 2,8 4, 1

I ADJUSTABLE GRIP FOR BOWLING BALL I L Filed Oct. 20, 1951 a Z; 4

ax/Maw United States Patent ADJUSTABLE GRIP FOR BOWLING BALL Leonard R. Nestor, st. Paul, Minn.

Application October 20, 1951, Serial No. 252,363

7 Claims. Cl. 273-63) This invention relates to an improved adjustable grip unit for bowling balls, and to bowling balls fitted therewith.

For accurate control of the ball in bowling, both the size andshape, and the relative location of the finger holes constituting the grip must be carefully and accurately adjusted to the individual bowler. After the proper measurements have been taken, under present practice, the ball is drilled, and the resulting finger-holes further shaped if desired, to provide a permanent grip. Thereafter, any adjustment of the grip may be accomplished only by plugging and re-drilling and re-shaping. Since adjustment is frequently desirable as the span of the bowlers hand varies, or the fingers become calloused, or for other reasons, this requirement results either in undue expense or, alternatively, in inaccurate bowling and in discomfort and dissatisfaction to the bowler.

It is therefore a primary object of the present invention to provide a bowling ball having an adjustable grip, whereby the bowler may readily, and as frequently as desired, re-adjust the grip to meet changing bodily conditions. Another object is to provide readily replaceable and interchangeable units for a bowling ball grip, so that the contour and positioning of the finger-holes may be altered at will. A further object is to provide an adjustable grip unit for insertion in a properly drilled bowling ball, whereby a ball may easily and economically be fitted with an adjustable grip.

These and other objects and advantages of my novel invention will be further pointed out, or will become apparent, as the description proceeds.

In the drawing, Figure 1 is a representation of a bowling ball fitted with one form of my adjustable gn'p unit, the latter being here shown largely in cut-away'longitudinal cross-section, and Figures 2 and 3 are similar cross-sectional views of alternative grip unit structures.

The adjustable grip of the bowling ball of Figure 1 comprises an adjustable thumb-hole unit 11 and a conventional drilled finger-hole 12. The same type of adjustable unit may be employed for the other finger-hole or holes where still wider latitude of adjustability is desired. For most users of a two-hole grip, a single adjustable finger-hole unit, preferably the thumb-hole unit, provides adequate adjustability. With a three-hole grip, it is usually desirable to provide an adjustable thumbhole unit and one adjustable finger-hole unit; a second adjustable finger-hole unit provides an additional but seldom necessary degree of adjustability.

I The adjustable finger-hole unit 11 of Figure 1 consists of anexternally tapered rigid cup-like plug 13, the axially offset hollow interior of the cup providing an axially offset finger-hole therein. The closed bottom of the cuplike plug is axially drilled and tapped to'provide an internally threaded hole. The tapered plug fits snugly within a tapered hole in the ball 10, in this case provided by an internally tapered cylindrical hollow cup-shaped shell 14 which is also axially drilled and tapped at the closed end of the cup, and which fits tightly and permaare nently within a cylindrical radial hole formed in the ball 10. A double-ended assembly screw 15, having an upper external thread portion 16 and a lower external thread portion 17, and with a transverse slot 18 in the end of the upper portion, completes the assembly.

When the screw 15 is turned in the assembling direction, as by means of a screwdriver fitting within the slot 18, the screw is drawn into the threaded aperture in the base of the shell 14, the same time the plug 13 is drawn into the shell. A tight fit is thus secured, with the finger-hole of the tapered plug 13 in the desired position. When adjustment becomes necessary, the screw is turned in the disassembling direction, whereupon the plug 13 is forced from the shell 14 and the screw is partly withdrawn from the threaded axial hole at the bottom of the shell 14. The plug may then be turned to a more desirable position, and again tightened in placeby means of the screw. It will of course be understood that the plug member 13 is held from rotating during such assembling and dis-assembling operations.

The screw 15 of Figure 1 will be seen to have a righthand lower thread 17 and a left-hand upper thread 16, each being of the same pitch, as illustrated in the drawing. The internal threads of the tapped holes in the shell 14 and plug 13 are likewise, in this case, respectively right and left hand threads. This system is advantageous in permitting equal strength of screw thread in each of the threaded components, which are all ordinarily required to be of the same composition as the remainder of the ball. The threads may be of square or other crosssection, rather than the conventional V-thread, if desired.

; An alternative screw-thread system is indicated in Figure 2, in which the two ends of the externally threaded assembly screw 25 and the corresponding internally threaded holes in the plug 23 and the ball 20 are all shown as having threads running in the same direction, here indicated as right-hand threads. The lower thread 27 is somewhat more coarse, i. e. has a higher pitch, than the upper thread 26. A hexagonal head 28 here replaces the slot 18 employed with the screw 13 of Figure l as a means for the application of twisting force to the screw.

The shell member 14 of Figure 1 is omitted in the structure of Figure 2, the lower threaded portion of the screw member 25 operating within a tapped hole formed directly in the ball on the same radial axis as that of the tapered hole into which the plug member 23 is fitted.

'Still a third structure is indicated in Figure 3, in which the hollow plug 33 fits into a hollow open tubular shell 34 having a cylindrical exterior and a tapered interior, the plug being drawn into the shell, and held in place therein, by a double, right-hand, externally threaded screw 35 having a lower threaded portion 37 operating in a corresponding internally-threaded hole formed directly in the ball 30 and a coarser, i. e. higher pitch, upperthreaded portion 36 operating in a corresponding in ternally-threaded hole located axially of the plug 33 and passing through the closed end thereof. The upper portion of the screw member 35 terminates in a hexagonal head- 38 which serves to provide means for turning the screw. I The plug 33 of Figure 3 will be seen to be formed with an axially located finger-hole, whereas the finger-holes of plug 23 of Figure'2 and of plug 13 of Figure 1 are illustrated as axially offset, i. e. with the center-line of the finger-hole parallel to, but somewhat removed from, the center-line of the tapered plug. In the structures of Figures 1 and 2; partial rotation of the hollow fingerhole plug will provide a change in the span, i. e. the dis-' tance between the holes, of the grip. In the structure of Figure 3, partial rotation of the plug has no effect on the span of the grip. However the plug 33 of Figure 3, like the plugs of Figures 1 and 2, may easily and quickly be removed and replaced by other plugs having diiferently shaped, or slanted, or otherwise altered finger-hole openings, whereby the grip of the ball may be altered or'adjusted to 'fit'the hand of the user.

The shell 14 of Figure 1 is provided with an external cylindrical shape for convenience in inserting into a drilled ball. A press fit is ordinarily 'found to be adequate to hold the shell permanently in place, although suitable adhesives or cements may be used if desired. The assembled unit may be inserted directly, or the shell alone may first be sealed in place, the screw and plug being added later.

Where proper tools are available, the shell of Figure 1 or 3 may be eliminated, as in the structure of Figure 2.

For example, the ball may first be drilled and the hole then reamed to the required taper so that the tapered plug 23 of Figure 2 fits the ball directly. A suitable threaded hole is of course also provided in the ball at the bottom and axially of the tapered hole. Here also the tapered plug may be easily adjusted, or removed and replaced, as desired. However the method requires great care and skill in drilling and reaming the taper, and consequently the three-part unit is ordinarily preferred, all things considered.

The double-ended screw of my invention provides, as hereinbefore noted, both for holding the hollow plug firmly in place and also for loosening the plug for repositioning or replacement. In the structure of Figure l, the two ends of the screw are threaded in opposite directions, Whereas in the structures of Figures 2 and 3 both ends of the screw are seen to be threaded in the same direction, which may be either rightor left-handed. However in each case the slope of the thread of the upper portion is different from the slope of the lower portion, and hence turning the screw while preventing rotation of the plug relative to the ball, serves to move the plug into or out of the ball depending on the direction in which the particular screw is turned.

The particular structure illustrated in Figure 3, wherein the upper threaded portion 36 is of a coarser pitch than the lower threaded portion 37, has an additional advantage. With such structure, the screw 35 must advance into the corresponding internally threaded hole in the ball in order to force the tapered plug out of the tapered shell; the threaded hole is therefore somewhat longer than the lower half of the screw. When replacement of the plug 33 becomes necessary, with this structure there is no likelihood of losing or misplacing the screw member, which necessarily remains well within the threaded hole when the plug is removed.

It will be understood that the figures of the drawing, or the components thereof, are not necessarily drawn to scale. For example the size and shape of the finger-hole, as well as its angle with the axis of the plug, may be quite diiferent depending on the requirements of the individual bowler. The threaded screw may be much larger than shown; for example, where the finger-hole is centered in the plug, as in Figure 3, the screw may be of the same diameter as the finger-hole. Such modifications are considered as being fully equivalent to the specific structures described and illustrated.

What I claim is as follows:

1. In a bowling ball, a grip structure comprising: an outwardly opening hollow frustum-shaped tapered plug member removably fitting within a correspondingly tapered radial hole in said ball, the degree of taper being 4 such that said plug is frictionally tightly retainable in said hole: and actuating means located at the interior end of said plug for drawing said plug into said hole and for expelling said plug from frictional retention within said hole; the outwardly opening hollow interior of said plug providing a finger-hole of said grip and afiording access to said actuating means.

2. An adjustable grip structure according to claim 1 in which the longitudinal axis of the finger-hole is re moved from the longitudinal axis of the plug.

3. In a bowling'ball, a grip structure comprising: a hollow outwardly opening internally tapered cup-like shell permanently fitted within a radial hole in said ball; a correspondingly externally tapered hollow outwardly opening plug member rotatably and removably fitting within said shell, the degree of taper being such that the plug is frictionally tightly retainable in the shell; and actuating means located at the interior end of said plug and said shell for drawing said plug into said shell and for expelling said plug from frictional retention within said hole; the outwardly opening hollow interior of said plug providing a finger-hole of said grip and affording access to said actuating means.

4. An adjustable grip structure according to claim 3 in which the longitudinal axis of the finger-hole is removed from the longitudinal axis of the plug.

5. A grip unit for insertion into a radial hole in a bowling ball, comprising: a hollow outwardly opening internally tapered cup-like shell adapted to be perinanently fitted within said radial hole; a correspondingly externally tapered hollow outwardly opening plug member rotatably and removably fitting within said shell, the degree of taper being such thatthe plug is frictionally tightly retainable in the shell; and actuating means located at the interior end of said plug and said shell for drawing said plug into said shell and for expelling said plug from frictional retention within said shell; the outwardly opening hollow interior of said plug providing a finger-hole of the grip of said ball and affording access to said actuating means.

6. An adjustable grip unit according to claim 5 in which the longitudinal axis of the finger-hole is removed from the longitudinal axis of the plug.

7. A grip unit for insertion into a tapered radial hole in a bowling ball, comprising: an outwardly opening hollow externally tapered plug member in the shape of a frustum, the degree of taper of said plug corresponding with that of said tapered hole and being such that said plug is frictionally tightly retainable in said hole; and actuating means located at the smaller end of said tapered plug for drawing said plug into said hole and for expelling said plug from frictional retention within said hole; the outwardly opening hollow interior of said plug affording access to said actuating means and providing a finger-hole when said unit is inserted into a bowling ball.

References Cited in the file of this patent UNITED STATES PATENTS 

